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97593cad00
linux/mm/kasan/kasan.h
Andrey Konovalov 97593cad00 kasan: sanitize objects when metadata doesn't fit 
KASAN marks caches that are sanitized with the SLAB_KASAN cache flag.
Currently if the metadata that is appended after the object (stores e.g.
stack trace ids) doesn't fit into KMALLOC_MAX_SIZE (can only happen with
SLAB, see the comment in the patch), KASAN turns off sanitization
completely.

With this change sanitization of the object data is always enabled.
However the metadata is only stored when it fits.  Instead of checking for
SLAB_KASAN flag accross the code to find out whether the metadata is
there, use cache->kasan_info.alloc/free_meta_offset.  As 0 can be a valid
value for free_meta_offset, introduce KASAN_NO_FREE_META as an indicator
that the free metadata is missing.

Without this change all sanitized KASAN objects would be put into
quarantine with generic KASAN.  With this change, only the objects that
have metadata (i.e.  when it fits) are put into quarantine, the rest is
freed right away.

Along the way rework __kasan_cache_create() and add claryfying comments.

Link: https://lkml.kernel.org/r/aee34b87a5e4afe586c2ac6a0b32db8dc4dcc2dc.1606162397.git.andreyknvl@google.com
Link: https://linux-review.googlesource.com/id/Icd947e2bea054cb5cfbdc6cf6652227d97032dcb
Co-developed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-22 12:55:09 -08:00

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __MM_KASAN_KASAN_H
#define __MM_KASAN_KASAN_H
#include <linux/kasan.h>
#include <linux/stackdepot.h>
#ifdef CONFIG_KASAN_HW_TAGS
#include <linux/static_key.h>
DECLARE_STATIC_KEY_FALSE(kasan_flag_stacktrace);
static inline bool kasan_stack_collection_enabled(void)
{
return static_branch_unlikely(&kasan_flag_stacktrace);
}
#else
static inline bool kasan_stack_collection_enabled(void)
{
return true;
}
#endif
extern bool kasan_flag_panic __ro_after_init;
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
#define KASAN_GRANULE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT)
#else
#include <asm/mte-kasan.h>
#define KASAN_GRANULE_SIZE MTE_GRANULE_SIZE
#endif
#define KASAN_GRANULE_MASK (KASAN_GRANULE_SIZE - 1)
#define KASAN_MEMORY_PER_SHADOW_PAGE (KASAN_GRANULE_SIZE << PAGE_SHIFT)
#define KASAN_TAG_KERNEL 0xFF /* native kernel pointers tag */
#define KASAN_TAG_INVALID 0xFE /* inaccessible memory tag */
#define KASAN_TAG_MAX 0xFD /* maximum value for random tags */
#ifdef CONFIG_KASAN_GENERIC
#define KASAN_FREE_PAGE 0xFF /* page was freed */
#define KASAN_PAGE_REDZONE 0xFE /* redzone for kmalloc_large allocations */
#define KASAN_KMALLOC_REDZONE 0xFC /* redzone inside slub object */
#define KASAN_KMALLOC_FREE 0xFB /* object was freed (kmem_cache_free/kfree) */
#define KASAN_KMALLOC_FREETRACK 0xFA /* object was freed and has free track set */
#else
#define KASAN_FREE_PAGE KASAN_TAG_INVALID
#define KASAN_PAGE_REDZONE KASAN_TAG_INVALID
#define KASAN_KMALLOC_REDZONE KASAN_TAG_INVALID
#define KASAN_KMALLOC_FREE KASAN_TAG_INVALID
#define KASAN_KMALLOC_FREETRACK KASAN_TAG_INVALID
#endif
#define KASAN_GLOBAL_REDZONE 0xF9 /* redzone for global variable */
#define KASAN_VMALLOC_INVALID 0xF8 /* unallocated space in vmapped page */
/*
* Stack redzone shadow values
* (Those are compiler's ABI, don't change them)
*/
#define KASAN_STACK_LEFT 0xF1
#define KASAN_STACK_MID 0xF2
#define KASAN_STACK_RIGHT 0xF3
#define KASAN_STACK_PARTIAL 0xF4
/*
* alloca redzone shadow values
*/
#define KASAN_ALLOCA_LEFT 0xCA
#define KASAN_ALLOCA_RIGHT 0xCB
#define KASAN_ALLOCA_REDZONE_SIZE 32
/*
* Stack frame marker (compiler ABI).
*/
#define KASAN_CURRENT_STACK_FRAME_MAGIC 0x41B58AB3
/* Don't break randconfig/all*config builds */
#ifndef KASAN_ABI_VERSION
#define KASAN_ABI_VERSION 1
#endif
/* Metadata layout customization. */
#define META_BYTES_PER_BLOCK 1
#define META_BLOCKS_PER_ROW 16
#define META_BYTES_PER_ROW (META_BLOCKS_PER_ROW * META_BYTES_PER_BLOCK)
#define META_MEM_BYTES_PER_ROW (META_BYTES_PER_ROW * KASAN_GRANULE_SIZE)
#define META_ROWS_AROUND_ADDR 2
struct kasan_access_info {
const void *access_addr;
const void *first_bad_addr;
size_t access_size;
bool is_write;
unsigned long ip;
};
/* The layout of struct dictated by compiler */
struct kasan_source_location {
const char *filename;
int line_no;
int column_no;
};
/* The layout of struct dictated by compiler */
struct kasan_global {
const void *beg; /* Address of the beginning of the global variable. */
size_t size; /* Size of the global variable. */
size_t size_with_redzone; /* Size of the variable + size of the red zone. 32 bytes aligned */
const void *name;
const void *module_name; /* Name of the module where the global variable is declared. */
unsigned long has_dynamic_init; /* This needed for C++ */
#if KASAN_ABI_VERSION >= 4
struct kasan_source_location *location;
#endif
#if KASAN_ABI_VERSION >= 5
char *odr_indicator;
#endif
};
/**
* Structures to keep alloc and free tracks *
*/
#define KASAN_STACK_DEPTH 64
struct kasan_track {
u32 pid;
depot_stack_handle_t stack;
};
#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY
#define KASAN_NR_FREE_STACKS 5
#else
#define KASAN_NR_FREE_STACKS 1
#endif
struct kasan_alloc_meta {
struct kasan_track alloc_track;
#ifdef CONFIG_KASAN_GENERIC
/*
* call_rcu() call stack is stored into struct kasan_alloc_meta.
* The free stack is stored into struct kasan_free_meta.
*/
depot_stack_handle_t aux_stack[2];
#else
struct kasan_track free_track[KASAN_NR_FREE_STACKS];
#endif
#ifdef CONFIG_KASAN_SW_TAGS_IDENTIFY
u8 free_pointer_tag[KASAN_NR_FREE_STACKS];
u8 free_track_idx;
#endif
};
struct qlist_node {
struct qlist_node *next;
};
/*
* Generic mode either stores free meta in the object itself or in the redzone
* after the object. In the former case free meta offset is 0, in the latter
* case it has some sane value smaller than INT_MAX. Use INT_MAX as free meta
* offset when free meta isn't present.
*/
#define KASAN_NO_FREE_META INT_MAX
struct kasan_free_meta {
#ifdef CONFIG_KASAN_GENERIC
/* This field is used while the object is in the quarantine.
* Otherwise it might be used for the allocator freelist.
*/
struct qlist_node quarantine_link;
struct kasan_track free_track;
#endif
};
struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
const void *object);
#ifdef CONFIG_KASAN_GENERIC
struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
const void *object);
#endif
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
static inline const void *kasan_shadow_to_mem(const void *shadow_addr)
{
return (void *)(((unsigned long)shadow_addr - KASAN_SHADOW_OFFSET)
<< KASAN_SHADOW_SCALE_SHIFT);
}
static inline bool addr_has_metadata(const void *addr)
{
return (addr >= kasan_shadow_to_mem((void *)KASAN_SHADOW_START));
}
/**
* check_memory_region - Check memory region, and report if invalid access.
* @addr: the accessed address
* @size: the accessed size
* @write: true if access is a write access
* @ret_ip: return address
* @return: true if access was valid, false if invalid
*/
bool check_memory_region(unsigned long addr, size_t size, bool write,
unsigned long ret_ip);
#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
static inline bool addr_has_metadata(const void *addr)
{
return true;
}
#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
void print_tags(u8 addr_tag, const void *addr);
#else
static inline void print_tags(u8 addr_tag, const void *addr) { }
#endif
void *find_first_bad_addr(void *addr, size_t size);
const char *get_bug_type(struct kasan_access_info *info);
void metadata_fetch_row(char *buffer, void *row);
#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
void print_address_stack_frame(const void *addr);
#else
static inline void print_address_stack_frame(const void *addr) { }
#endif
bool kasan_report(unsigned long addr, size_t size,
bool is_write, unsigned long ip);
void kasan_report_invalid_free(void *object, unsigned long ip);
struct page *kasan_addr_to_page(const void *addr);
depot_stack_handle_t kasan_save_stack(gfp_t flags);
void kasan_set_track(struct kasan_track *track, gfp_t flags);
void kasan_set_free_info(struct kmem_cache *cache, void *object, u8 tag);
struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
void *object, u8 tag);
#if defined(CONFIG_KASAN_GENERIC) && \
(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
bool quarantine_put(struct kmem_cache *cache, void *object);
void quarantine_reduce(void);
void quarantine_remove_cache(struct kmem_cache *cache);
#else
static inline bool quarantine_put(struct kmem_cache *cache, void *object) { return false; }
static inline void quarantine_reduce(void) { }
static inline void quarantine_remove_cache(struct kmem_cache *cache) { }
#endif
#ifndef arch_kasan_set_tag
static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
{
return addr;
}
#endif
#ifndef arch_kasan_get_tag
#define arch_kasan_get_tag(addr) 0
#endif
#define set_tag(addr, tag) ((void *)arch_kasan_set_tag((addr), (tag)))
#define get_tag(addr) arch_kasan_get_tag(addr)
#ifdef CONFIG_KASAN_HW_TAGS
#ifndef arch_enable_tagging
#define arch_enable_tagging()
#endif
#ifndef arch_init_tags
#define arch_init_tags(max_tag)
#endif
#ifndef arch_get_random_tag
#define arch_get_random_tag() (0xFF)
#endif
#ifndef arch_get_mem_tag
#define arch_get_mem_tag(addr) (0xFF)
#endif
#ifndef arch_set_mem_tag_range
#define arch_set_mem_tag_range(addr, size, tag) ((void *)(addr))
#endif
#define hw_enable_tagging() arch_enable_tagging()
#define hw_init_tags(max_tag) arch_init_tags(max_tag)
#define hw_get_random_tag() arch_get_random_tag()
#define hw_get_mem_tag(addr) arch_get_mem_tag(addr)
#define hw_set_mem_tag_range(addr, size, tag) arch_set_mem_tag_range((addr), (size), (tag))
#endif /* CONFIG_KASAN_HW_TAGS */
#ifdef CONFIG_KASAN_SW_TAGS
u8 random_tag(void);
#elif defined(CONFIG_KASAN_HW_TAGS)
static inline u8 random_tag(void) { return hw_get_random_tag(); }
#else
static inline u8 random_tag(void) { return 0; }
#endif
#ifdef CONFIG_KASAN_HW_TAGS
static inline void poison_range(const void *address, size_t size, u8 value)
{
hw_set_mem_tag_range(kasan_reset_tag(address),
round_up(size, KASAN_GRANULE_SIZE), value);
}
static inline void unpoison_range(const void *address, size_t size)
{
hw_set_mem_tag_range(kasan_reset_tag(address),
round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
}
static inline bool check_invalid_free(void *addr)
{
u8 ptr_tag = get_tag(addr);
u8 mem_tag = hw_get_mem_tag(addr);
return (mem_tag == KASAN_TAG_INVALID) ||
(ptr_tag != KASAN_TAG_KERNEL && ptr_tag != mem_tag);
}
#else /* CONFIG_KASAN_HW_TAGS */
void poison_range(const void *address, size_t size, u8 value);
void unpoison_range(const void *address, size_t size);
bool check_invalid_free(void *addr);
#endif /* CONFIG_KASAN_HW_TAGS */
/*
* Exported functions for interfaces called from assembly or from generated
* code. Declarations here to avoid warning about missing declarations.
*/
asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
void __asan_register_globals(struct kasan_global *globals, size_t size);
void __asan_unregister_globals(struct kasan_global *globals, size_t size);
void __asan_handle_no_return(void);
void __asan_alloca_poison(unsigned long addr, size_t size);
void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom);
void __asan_load1(unsigned long addr);
void __asan_store1(unsigned long addr);
void __asan_load2(unsigned long addr);
void __asan_store2(unsigned long addr);
void __asan_load4(unsigned long addr);
void __asan_store4(unsigned long addr);
void __asan_load8(unsigned long addr);
void __asan_store8(unsigned long addr);
void __asan_load16(unsigned long addr);
void __asan_store16(unsigned long addr);
void __asan_loadN(unsigned long addr, size_t size);
void __asan_storeN(unsigned long addr, size_t size);
void __asan_load1_noabort(unsigned long addr);
void __asan_store1_noabort(unsigned long addr);
void __asan_load2_noabort(unsigned long addr);
void __asan_store2_noabort(unsigned long addr);
void __asan_load4_noabort(unsigned long addr);
void __asan_store4_noabort(unsigned long addr);
void __asan_load8_noabort(unsigned long addr);
void __asan_store8_noabort(unsigned long addr);
void __asan_load16_noabort(unsigned long addr);
void __asan_store16_noabort(unsigned long addr);
void __asan_loadN_noabort(unsigned long addr, size_t size);
void __asan_storeN_noabort(unsigned long addr, size_t size);
void __asan_report_load1_noabort(unsigned long addr);
void __asan_report_store1_noabort(unsigned long addr);
void __asan_report_load2_noabort(unsigned long addr);
void __asan_report_store2_noabort(unsigned long addr);
void __asan_report_load4_noabort(unsigned long addr);
void __asan_report_store4_noabort(unsigned long addr);
void __asan_report_load8_noabort(unsigned long addr);
void __asan_report_store8_noabort(unsigned long addr);
void __asan_report_load16_noabort(unsigned long addr);
void __asan_report_store16_noabort(unsigned long addr);
void __asan_report_load_n_noabort(unsigned long addr, size_t size);
void __asan_report_store_n_noabort(unsigned long addr, size_t size);
void __asan_set_shadow_00(const void *addr, size_t size);
void __asan_set_shadow_f1(const void *addr, size_t size);
void __asan_set_shadow_f2(const void *addr, size_t size);
void __asan_set_shadow_f3(const void *addr, size_t size);
void __asan_set_shadow_f5(const void *addr, size_t size);
void __asan_set_shadow_f8(const void *addr, size_t size);
void __hwasan_load1_noabort(unsigned long addr);
void __hwasan_store1_noabort(unsigned long addr);
void __hwasan_load2_noabort(unsigned long addr);
void __hwasan_store2_noabort(unsigned long addr);
void __hwasan_load4_noabort(unsigned long addr);
void __hwasan_store4_noabort(unsigned long addr);
void __hwasan_load8_noabort(unsigned long addr);
void __hwasan_store8_noabort(unsigned long addr);
void __hwasan_load16_noabort(unsigned long addr);
void __hwasan_store16_noabort(unsigned long addr);
void __hwasan_loadN_noabort(unsigned long addr, size_t size);
void __hwasan_storeN_noabort(unsigned long addr, size_t size);
void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);
#endif
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